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For historical information, Wikipedia has an article on Type B1 submarine.
Type B1 submarine
B1 sub
Role Submarine
Operators Japan
No. of positions 2
Position 1 Helmsman
Stern torpedo tubes
Position 2 Dual Type 96 AA gun

The Type B1 submarine is a Japanese submarine.


The Japanese Type B1 Otsu-gata submarine class was developed in the late 1930s from the short-range K6 submarines. The goal was to create a large, long-range scouting boat that could locate targets for the C1 attack submarines. For this task the B1 submarines had a small hangar in front of the streamlined conning tower, in which an Yokosuka E14Y seaplane was carried. The latter could be launched from a catapult mounted on the forward deck, giving the submarine a very large reconnaissance radius. Six units of the B1 class were completed prior the outbreak of the pacific war and participated in the Pearl Harbor attack. The B1 class proved to be a successful design, so an additional batch of 14 ships was ordered by the Japanese navy.

Apart from sinking a consideral amount of enemy merchant and supply shipping, the submarines achieved some victories against capital ships. For example I-26 damaged the aircraft carrier Saratoga in August 1942, taking her out of the Guadalcanal campaign. I-19 sunk the aircraft carrier Wasp two weeks later. The same torpedo salvo that sank Wasp also damaged the battleship North Carolina and sank the destroyer O'Brien. I-26 also was responsible for the sinking of the cruiser Juneau which had been badly damaged in the Naval Battle of Guadalcanal, November 1942. Because of their excellent range, the B1 class submarines were sometimes used to exchange diplomats and supplies between Japan and the other Axis. For example, I-30 was sent to the German-occupied french harbor Lorient in May 1942 in order to supply the Japanese with advanced German radar technology. But on its return the boat was sunk by a British mine off Singapore and got lost along with the Würzburg radar it was carrying. A fate common to the rest of the class: By the end of 1944, even the last two boats of the class have been sunk by the enemy.

In Battlegroup42, the B1 class submarine has a total of six torpedo tubes at the stern. It also comes with a dual Type 96 AA gun for aerial defense. Unlike other submarines in the mod, a Nakajima A6M2-N seaplane spawns in front of the conning tower, which can be launched by catapult.


A seaplane launched by a B1 class submarine is credited with the only conventional air attack carried out against the U.S. mainland during the Second World War, when a "Glen" from I-25 dropped incendiary bombs on the forests of Oregon in an attempt to start a forest fire.

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